Ancillary ligand stabilized metal complexes (e.g., organometallic complexes) are useful as catalysts, additives, stoichiometric reagents, monomers, solid state precursors, therapeutic reagents and drugs. The ancillary ligand system comprises organic substituents that bind to the metal center(s), remain associated with the metal center(s), and therefore provide an opportunity to modify the shape, electronic and chemical properties of the active metal center(s) of the organometallic complex.
Certain organometallic complexes are catalysts for reactions such as oxidation, reduction, hydrogenation, hydrosilylation, hydrocyanation, hydroformylation, polymerization, carbonylation, isomerization, metathesis, carbon-hydrogen activation, cross-coupling, Friedel-Craftis acylation and alkylation, hydration, dimerization, trimerization, oligomerization, Diels-Alder reactions and other transformations. Organometallic complexes can be prepared by combining an ancillary ligand precursor with a suitable metal precursor in a suitable solvent at a suitable temperature.
One example of the use of organometallic complexes this is in the field of single- sited olefin polymerization catalysis. The active site typically comprises an ancillary ligand-stabilized, coordinatively unsaturated transition metal alkyl complex. Although a variety of such organometallic catalysts have been discovered over the past 15 years, the discovery process is laborious, entailing the individual synthesis of potentially catalytic materials and subsequently screening them for catalytic activity.
It is always a desire to discover new ligand systems that, once connected to a metal center, will catalyze reactions differently from known ligand systems. This invention provides new ancillary ligands that may be attached to a metal center. Once attached, such ligands modify the electronic and steric environment and may catalyze reactions differently from known systems.